The invention relates to a catheter connecting head with at least one duct in a base member for the connection of an infusion system.
In a conventional catheter of this type (DAS[German Published Application] No. 2,238,722), a hollow connecting piece consists of a catheter boss, a connecting boss for the infusion system or for a further catheter, and an elastic hose section arranged between both bosses. The wall of the hose section, which latter can be bent laterally, constitutes a zone of elastic, self-sealing material, for example, rubber, which can be penetrated by a hollow needle.
Apart from the fact that, when penetrating the rubber wall with the aid of a sharp tip of a metal cannula, there is no guarantee against scraping off rather small or extremely small parts of the rubber wall and preventing such parts from passing directly into the bloodstream, this conventional arrangement furthermore exhibits the danger that the rubber wall is once more penetrated by a metal cannula, thus damaging the catheter or the catheter insertion tube which had remained in the blood vessel from the first puncturing procedure.
Based on the above-described state of the art, the invention has an object of providing a catheter connecting head for a vein puncturing and self-retaining cannula kit, which connecting head, on the one hand, can be handled conveniently and safely as far as the physician is concerned and, on the other hand, reduces to a minimum or even entirely eliminates the danger of embolism or infection as far as the patient is concerned.
This object has been attained in a preferred embodiment according to this invention by the construction of the duct for the puncture cannula such that, upon withdrawal of the puncture cannula, the duct is automatically closed and locked by closure and locking elements such that reinsertion is not possible. Due to the fact that the puncture cannula duct is automatically sealed and closed when the puncture cannula is retracted and that this puncture cannula duct, as well as optionally additional ducts of the connecting head, are automatically sealed with respect to the surroundings with the aid of mechanical sealing elements, it is impossible to introduce additional puncture cannulas into the duct or ducts of the base member and thus already installed catheters cannot be accidentally damaged. Moreover, the sealing elements ensure that neither air bubbles nor any dirt particles can enter the bloodstream, whereby the danger of embolisms is substantially reduced.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which shown, for purposes of illustration only, several embodiments in accordance with the present invention.